Gamespot interviewed John Drake of Harmonix Music Systems and they gave us a great view of how Fantasia: Music Evolved works. Using body gestures to control the screen, the music changes and, of course, evolves. The movements remind me of the Sorcerer’s Apprentice, which they make mention of as well. You are the sorcerer’s apprentice and you are exploring an undersea realm much like Mickey Mouse (or Dave) with the mops and brooms.
There are over 25 songs to start off Fantasia: Music Evolved that have multiple remixed paths when the game launches. More will become available after launch through downloadable content (known as DLC’s). The launch date is not firm on this game aside from being in 2014. According to John Drake, they are aiming for after the holiday season.